Buggy code:
public class Link extends Control { String text ; TextLayout layout ; Color linkColor ; Color linkDisabledColor ; Point [ ] offsets ; Point selection ; String [ ] ids ; int [ ] mnemonics ; int focusIndex ; static final RGB LINK_FOREGROUND = new RGB ( 0 , 51 , 153 ) ; static final RGB LINK_DISABLED_FOREGROUND = new RGB ( 172 , 168 , 153 ) ; public Link ( Composite parent , int style ) { } public void addSelectionListener ( SelectionListener listener ) { } public Point computeSize ( int wHint , int hHint , boolean changed ) { } void createHandle ( int index ) { } void createWidget ( int index ) { } void enableWidget ( boolean enabled ) { } String getNameText ( ) { } Rectangle [ ] getRectangles ( int linkIndex ) { } public String getText ( ) { } int gtk_button_press_event ( int widget , int event ) { } int gtk_button_release_event ( int widget , int event ) { } int gtk_event_after ( int widget , int gdkEvent ) { } int gtk_expose_event ( int widget , int eventPtr ) { } int gtk_key_press_event ( int widget , int eventPtr ) { } int gtk_motion_notify_event ( int widget , int event ) { } void releaseWidget ( ) { } public void removeSelectionListener ( SelectionListener listener ) { } String parse ( String string ) { int length = string . length ( ) ; offsets = new Point [ length // 4 ] ; ids = new String [ length // 4 ] ; <START_BUG> mnemonics = new int [ length // 4 ] ; <END_BUG> StringBuffer result = new StringBuffer ( ) ; char [ ] buffer = new char [ length ] ; string . getChars ( 0 , string . length ( ) , buffer , 0 ) ; int index = 0 ; int state = 0 ; int linkIndex = 0 ; int start = 0 ; int tagStart = 0 ; int linkStart = 0 ; int endtagStart = 0 ; int refStart = 0 ; while ( index < length ) { char c = Character . toLowerCase ( buffer [ index ] ) ; switch ( state ) { case 0 : if ( c == '<' ) { tagStart = index ; state ++ ; } break ; case 1 : if ( c == 'a' ) state ++ ; break ; case 2 : switch ( c ) { case 'h' : state = 7 ; break ; case '>' : linkStart = index + 1 ; state ++ ; break ; default : if ( Character . isWhitespace ( c ) ) break ; else state = 13 ; } break ; case 3 : if ( c == '<' ) { endtagStart = index ; state ++ ; } break ; case 4 : state = ( c == '//' ) ? state + 1 : 3 ; break ; case 5 : state = ( c == 'a' ) ? state + 1 : 3 ; break ; case 6 : if ( c == '>' ) { mnemonics [ linkIndex ] = parseMnemonics ( buffer , start , tagStart , result ) ; int offset = result . length ( ) ; parseMnemonics ( buffer , linkStart , endtagStart , result ) ; offsets [ linkIndex ] = new Point ( offset , ( ( result . length ( ) ) - 1 ) ) ; if ( ( ids [ linkIndex ] ) == null ) { ids [ linkIndex ] = new String ( buffer , linkStart , ( endtagStart - linkStart ) ) ; } linkIndex ++ ; start = tagStart = linkStart = endtagStart = refStart = index + 1 ; state = 0 ; } else { state = 3 ; } break ; case 7 : state = ( c == 'r' ) ? state + 1 : 0 ; break ; case 8 : state = ( c == 'e' ) ? state + 1 : 0 ; break ; case 9 : state = ( c == 'f' ) ? state + 1 : 0 ; break ; case 10 : state = ( c == '=' ) ? state + 1 : 0 ; break ; case 11 : if ( c == '"' ) { state ++ ; refStart = index + 1 ; } else { state = 0 ; } break ; case 12 : if ( c == '"' ) { ids [ linkIndex ] = new String ( buffer , refStart , ( index - refStart ) ) ; state = 2 ; } break ; case 13 : if ( Character . isWhitespace ( c ) ) { state = 0 ; } else if ( c == '=' ) { state ++ ; } break ; case 14 : state = ( c == '"' ) ? state + 1 : 0 ; break ; case 15 : if ( c == '"' ) state = 2 ; break ; default : state = 0 ; break ; } index ++ ; } if ( start < length ) { int tmp = parseMnemonics ( buffer , start , tagStart , result ) ; int mnemonic = parseMnemonics ( buffer , linkStart , index , result ) ; if ( mnemonic == ( - 1 ) ) mnemonic = tmp ; mnemonics [ linkIndex ] = mnemonic ; } else { mnemonics [ linkIndex ] = - 1 ; } if ( ( offsets . length ) != linkIndex ) { Point [ ] newOffsets = new Point [ linkIndex ] ; System . arraycopy ( offsets , 0 , newOffsets , 0 , linkIndex ) ; offsets = newOffsets ; String [ ] newIDs = new String [ linkIndex ] ;

Fix:
mnemonics = new int [ ( length // 4 ) + 1 ] ;